kmodloader: add module alias awareness

To achieve this, the following changes are made

 - scan module folders before scaning loaded modules
 - struct module was splited into struct module_node for the avl tree
   and struct module for storing actual info about modules

The other minor fix is that module.opts is now freed in free_modules()
when appliable

Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>

diff --git a/kmodloader.c b/kmodloader.c
index c780379ed47f4349a2bc0c96d3bd9481943ea79f..bcb213b36757ead6ad21b8bd94a21483e5d9b457 100644 (file)
--- a/kmodloader.c
+++ b/kmodloader.c
@@ -45,22 +45,31 @@ enum {
 };
 
 struct module {
-       struct avl_node avl;
-
        char *name;
        char *depends;
        char *opts;
+       char **aliases;
+       int naliases;
 
        int size;
        int usage;
        int state;
        int error;
+       int refcnt;                     /* number of references from module_node.m */
+};
+
+struct module_node {
+       struct avl_node avl;
+       struct module *m;
+       bool is_alias;
 };
 
 static struct avl_tree modules;
 
 static char **module_folders = NULL;
 
+static void free_module(struct module *m);
+
 static int init_module_folders(void)
 {
        int n = 0;
@@ -106,16 +115,26 @@ static int init_module_folders(void)
 
 static struct module *find_module(const char *name)
 {
-       struct module *m;
-       return avl_find_element(&modules, name, m, avl);
+       struct module_node *mn;
+       mn = avl_find_element(&modules, name, mn, avl);
+       if (mn)
+               return mn->m;
+       else
+               return NULL;
 }
 
 static void free_modules(void)
 {
-       struct module *m, *tmp;
+       struct module_node *mn, *tmp;
+
+       avl_remove_all_elements(&modules, mn, avl, tmp) {
+               struct module *m = mn->m;
 
-       avl_remove_all_elements(&modules, m, avl, tmp)
-               free(m);
+               m->refcnt -= 1;
+               if (m->refcnt == 0)
+                       free_module(m);
+               free(mn);
+       }
 }
 
 static char* get_module_path(char *name)
@@ -208,19 +227,43 @@ static int elf_find_section(char *map, const char *section, unsigned int *offset
        return -1;
 }
 
+static struct module_node *
+alloc_module_node(const char *name, struct module *m, bool is_alias)
+{
+       struct module_node *mn;
+       char *_name;
+
+       mn = calloc_a(sizeof(*mn),
+               &_name, strlen(name) + 1);
+       if (mn) {
+               mn->avl.key = strcpy(_name, name);
+               mn->m = m;
+               mn->is_alias = is_alias;
+               avl_insert(&modules, &mn->avl);
+               m->refcnt += 1;
+       }
+       return mn;
+}
+
 static struct module *
-alloc_module(const char *name, const char *depends, int size)
+alloc_module(const char *name, const char * const *aliases, int naliases, const char *depends, int size)
 {
        struct module *m;
        char *_name, *_dep;
+       char **_aliases;
+       int i, len_aliases;
 
+       len_aliases = naliases * sizeof(aliases[0]);
+       for (i = 0; i < naliases; i++)
+               len_aliases += strlen(aliases[i]) + 1;
        m = calloc_a(sizeof(*m),
                &_name, strlen(name) + 1,
-               &_dep, depends ? strlen(depends) + 2 : 0);
+               &_dep, depends ? strlen(depends) + 2 : 0,
+               &_aliases, len_aliases);
        if (!m)
                return NULL;
 
-       m->avl.key = m->name = strcpy(_name, name);
+       m->name = strcpy(_name, name);
        m->opts = 0;
 
        if (depends) {
@@ -231,13 +274,40 @@ alloc_module(const char *name, const char *depends, int size)
                        _dep++;
                }
        }
-
        m->size = size;
-       avl_insert(&modules, &m->avl);
+       m->naliases = naliases;
+       if (naliases == 0)
+               m->aliases = NULL;
+       else {
+               char *ptr = (char *)_aliases + naliases * sizeof(_aliases[0]);
+               int len;
+
+               i = 0;
+               do {
+                       len = strlen(aliases[i]) + 1;
+                       memcpy(ptr, aliases[i], len);
+                       _aliases[i] = ptr;
+                       ptr += len;
+                       i++;
+               } while (i < naliases);
+               m->aliases = _aliases;
+       }
+
+       m->refcnt = 0;
+       alloc_module_node(m->name, m, false);
+       for (i = 0; i < m->naliases; i++)
+               alloc_module_node(m->aliases[i], m, true);
 
        return m;
 }
 
+static void free_module(struct module *m)
+{
+       if (m->opts)
+               free(m->opts);
+       free(m);
+}
+
 static int scan_loaded_modules(void)
 {
        size_t buf_len = 0;
@@ -262,7 +332,11 @@ static int scan_loaded_modules(void)
                if (!m.name || !m.depends)
                        continue;
 
-               n = alloc_module(m.name, m.depends, m.size);
+               n = find_module(m.name);
+               if (!n) {
+                       /* possibly a module outside /lib/modules/<ver>/ */
+                       n = alloc_module(m.name, NULL, 0, m.depends, m.size);
+               }
                n->usage = m.usage;
                n->state = LOADED;
        }
@@ -277,6 +351,8 @@ static struct module* get_module_info(const char *module, const char *name)
        int fd = open(module, O_RDONLY);
        unsigned int offset, size;
        char *map = MAP_FAILED, *strings, *dep = NULL;
+       const char *aliases[32];
+       int naliases = 0;
        struct module *m = NULL;
        struct stat s;
 
@@ -317,10 +393,17 @@ static struct module* get_module_info(const char *module, const char *name)
                sep++;
                if (!strncmp(strings, "depends=", len + 1))
                        dep = sep;
+               else if (!strncmp(strings, "alias=", len + 1)) {
+                       if (naliases < ARRAY_SIZE(aliases))
+                               aliases[naliases++] = sep;
+                       else
+                               ULOG_WARN("module %s has more than %d aliases: truncated",
+                                               name, ARRAY_SIZE(aliases));
+               }
                strings = &sep[strlen(sep)];
        }
 
-       m = alloc_module(name, dep, s.st_size);
+       m = alloc_module(name, aliases, naliases, dep, s.st_size);
 
        if (m)
                m->state = SCANNED;
@@ -530,16 +613,24 @@ static int iterations = 0;
 static int load_modprobe(void)
 {
        int loaded, todo;
+       struct module_node *mn;
        struct module *m;
 
-       avl_for_each_element(&modules, m, avl)
+       avl_for_each_element(&modules, mn, avl) {
+               if (mn->is_alias)
+                       continue;
+               m = mn->m;
                if (m->state == PROBE)
                        load_moddeps(m);
+       }
 
        do {
                loaded = 0;
                todo = 0;
-               avl_for_each_element(&modules, m, avl) {
+               avl_for_each_element(&modules, mn, avl) {
+                       if (mn->is_alias)
+                               continue;
+                       m = mn->m;
                        if ((m->state == PROBE) && (!deps_available(m, 0))) {
                                if (!insert_module(get_module_path(m->name), (m->opts) ? (m->opts) : (""))) {
                                        m->state = LOADED;
@@ -663,13 +754,17 @@ static int main_rmmod(int argc, char **argv)
 
 static int main_lsmod(int argc, char **argv)
 {
+       struct module_node *mn;
        struct module *m;
        char *dep;
 
        if (scan_loaded_modules())
                return -1;
 
-       avl_for_each_element(&modules, m, avl)
+       avl_for_each_element(&modules, mn, avl) {
+               if (mn->is_alias)
+                       continue;
+               m = mn->m;
                if (m->state == LOADED) {
                        printf("%-20s%8d%3d ",
                                m->name, m->size, m->usage);
@@ -684,6 +779,7 @@ static int main_lsmod(int argc, char **argv)
                        }
                        printf("\n");
                }
+       }
 
        free_modules();
 
@@ -721,6 +817,7 @@ static int main_modinfo(int argc, char **argv)
 
 static int main_modprobe(int argc, char **argv)
 {
+       struct module_node *mn;
        struct module *m;
        char *name;
        char *mod = NULL;
@@ -734,10 +831,10 @@ static int main_modprobe(int argc, char **argv)
        if (!mod)
                return print_usage("modprobe");
 
-       if (scan_loaded_modules())
+       if (scan_module_folders())
                return -1;
 
-       if (scan_module_folders())
+       if (scan_loaded_modules())
                return -1;
 
        name = get_module_name(mod);
@@ -758,9 +855,13 @@ static int main_modprobe(int argc, char **argv)
                        ULOG_ERR("%d module%s could not be probed\n",
                                 fail, (fail == 1) ? ("") : ("s"));
 
-                       avl_for_each_element(&modules, m, avl)
+                       avl_for_each_element(&modules, mn, avl) {
+                               if (mn->is_alias)
+                                       continue;
+                               m = mn->m;
                                if ((m->state == PROBE) || m->error)
                                        ULOG_ERR("- %s\n", m->name);
+                       }
                }
        }
 
@@ -773,6 +874,7 @@ static int main_loader(int argc, char **argv)
 {
        int gl_flags = GLOB_NOESCAPE | GLOB_MARK;
        char *dir = "/etc/modules.d/";
+       struct module_node *mn;
        struct module *m;
        glob_t gl;
        char *path;
@@ -785,12 +887,12 @@ static int main_loader(int argc, char **argv)
        strcpy(path, dir);
        strcat(path, "*");
 
-       if (scan_loaded_modules()) {
+       if (scan_module_folders()) {
                free (path);
                return -1;
        }
 
-       if (scan_module_folders()) {
+       if (scan_loaded_modules()) {
                free (path);
                return -1;
        }
@@ -843,9 +945,13 @@ static int main_loader(int argc, char **argv)
                ULOG_ERR("%d module%s could not be probed\n",
                         fail, (fail == 1) ? ("") : ("s"));
 
-               avl_for_each_element(&modules, m, avl)
+               avl_for_each_element(&modules, mn, avl) {
+                       if (mn->is_alias)
+                               continue;
+                       m = mn->m;
                        if ((m->state == PROBE) || (m->error))
                                ULOG_ERR("- %s - %d\n", m->name, deps_available(m, 1));
+               }
        } else {
                ULOG_INFO("done loading kernel modules from %s\n", path);
        }